1. Field of the Invention
The present invention relates to an optical switch and an optical switch system which are used in optical communication and photonic switching, particularly to an optical switch and an optical switch system in which the necessary amount of hardware can be reduced.
2. Description of the Related Art
In photonic switching such as an optical cross-connecting system in which a light signal is used as light without being converted to an electric signal in a node to edit a light propagation path, a node scale can be reduced, which contributes to communication cost reduction. An optical switch technique is important for constituting such node. As a conventional optical switch, there have been proposed a switch prepared using lithium niobate, an optical crossbar switch using a semiconductor optical amplifier as a gate switch, and the like. Various proposals have also been submitted for optical switch systems such as an optical switch network using these optical switches.
For example, a conventional optical switch system aiming at application to an interconnected network of parallel computers is proposed in the Proceedings for 1996 General Convention of the Institute of Electronics, Information and Communication Engineers of Japan (IEICE), No. SB-9-5. In this optical switch system, an optical crossbar switch employing a semiconductor optical amplifier as a gate switch is used. Moreover, an optical switch network in which a transmission capacity per port is increased by using a wavelength-division multiplexing technology is also proposed in the Proceedings of 1996 Communication Society meeting of IEICE, No.B-1072.
However, the optical crossbar switch used in the above-described conventional optical switch system requires semiconductor optical amplifiers by the square of the number of input/output ports. Therefore, when switch scale increases, cost rapidly increases. There is further problem that it becomes very difficult to mount the switch. For example, a 4xc3x974 optical crossbar switch with four input ports and four output ports requires 16 semiconductor optical amplifiers, but a 16xc3x9716 optical crossbar switch requires 256 amplifiers, and a 64xc3x9764 optical crossbar switch requires 4096 semiconductor optical amplifiers.
Moreover, in the optical switch system using the wavelength-division multiplexing technology, in order to reduce the number of gates, a wavelength-division multiplexing light source is necessary. This raises a problem that it becomes difficult to inexpensively constitute the optical switch system.
An object of the present invention is to provide an optical switch system which can reduce the number of necessary optical switches and which is small in size and low in cost.
According to the present invention, there is provided an optical switch comprising: at least one optical fiber pair arranged so that light emitted from a first optical fiber is coupled to a second optical fiber via a void; and an optical breaker for interrupting the optical coupling between the first and second optical fibers.
According to the present invention, there is provided an optical switch system comprising: at least one optical branching unit for branching at least one input light signal to a predetermined number of branched output lights; at least one optical combining unit for combining one of the branched output lights of at least one optical branching unit; and at least one optical switch inserted between the optical branching unit and at least one optical combining unit to which each of the branched output lights of the optical branching unit is supplied.